The disclosed embodiments relate to a catheter that is capable of, for example, passing by or through a hard lesion. Japanese Unexamined Patent Application Publication No. 2007-244492 discloses a traditional catheter having a metallic distal end with sufficient hardness. Thus, the catheter is inserted into a hard lesion formed inside, for example, a blood vessel, a bile duct, or a pancreatic duct, or the catheter is inserted into bone in order to suck bone marrow. However, the distal end of the catheter of Japanese Unexamined Patent Application Publication No. 2007-244492 does not also have flexibility. U.S. Patent Application Publication No. 2008/0255507 discloses a traditional catheter in which a resin distal end tip is provided with a groove in order to provide flexibility.